REVIEW Open Access

Acute appendicitis: proposal of a newcomprehensive grading system based onclinical, imaging and laparoscopic findingsCarlos Augusto Gomes1*, Massimo Sartelli2, Salomone Di Saverio3, Luca Ansaloni4, Fausto Catena5,Federico Coccolini4, Kenji Inaba6, Demetrios Demetriades6,7, Felipe Couto Gomes8 and Camila Couto Gomes9

Abstract

Advances in the technology and improved access to imaging modalities such as Computed Tomography andlaparoscopy have changed the contemporary diagnostic and management of acute appendicitis. Complicatedappendicitis (phlegmon, abscess and/ or diffuse peritonitis), is now reliably distinguished from uncomplicatedcases. Therefore, a new comprehensive grading system for acute appendicitis is necessary. The goal is review andupdate the laparoscopic grading system of acute appendicitis and to provide a new standardized classificationsystem to allow more uniform patient stratification. During the last World Society of Emergency Surgery Congressin Israel (July, 2015), a panel involving Acute Appendicitis Experts and the author’s discussed many current aspects aboutthe acute appendicitis between then, it will be submitted a new comprehensive disease grading system. It was idealizedbased on three aspect of the disease (clinical and imaging presentation and laparoscopic findings). The new gradingsystem may provide a standardized system to allow more uniform patient stratification for appendicitis research.In addition, may aid in determining optimal management according to grade. Lastly, what we want is to draw amulticenter observational study within the World Society of Emergency Surgery (WSES) based on this design.

Keywords: Appendicitis, Appendectomy, Laparoscopy, Treatment, Classification

BackgroundAppendicitis is the most common cause of an acute sur-gical abdomen, with an estimated lifetime prevalence of7–8 %. Despite advances in diagnosis and treatment, it isstill associated with significant morbidity (10 %) andmortality (1–5 %) [1]. The clinical history and physicalexamination represent the most important tools for earlydiagnosis of the disease. The overall accuracy for diagnos-ing acute appendicitis is approximately 90 %, with a false-negative appendectomy rate of 10 %. This is more frequentin atypical cases, especially in women of childbearing age,because the symptoms often overlap with others condi-tions [2, 3]. Recently 182 patients with suspicion of acuteappendicitis were stratified to low, intermediate, and high

probability of appendicitis by two different clinical scores(AIR / Alvarado) and by an experienced surgeon. The AIRscore was especially good at identifying patients with highprobability of appendicitis with a specificity of 0.97 for allappendicitis and 0.92 for advanced appendicitis, com-pared with 0.91 and 0.77, respectively, for the surgeonand Alvarado score. Therefore, in this series, the AIRscore had both higher sensitivity and specificity thanthe Alvarado score and the experienced surgeon in theclinical diagnosis of the disease [4].

ImagingThe clinical scores represent an excellent and useful toolfor pre-operative diagnosis of acute appendicitis, butregardless its accuracy it cannot be applied as a gradingsystem for acute appendicitis, especially attempting todistinguish different complicated grades of the disease[5]. As we know, novel scoring systems are beingdescribed and introduced into clinical practice, based onclinical and imaging (CT and/or US). In addition, less

* Correspondence: caxiaogomes@gmail.com1Surgery Department, Therezinha de Jesus University Hospital, Medical andHealth Science School, Surgery Unit, Federal University of Juiz de Fora (UFJF),Rua Senador Salgado Filho 510 / 1002, Bairro Bom Pastor, Juiz de Fora, MinasGerais 36021-660, BrasilFull list of author information is available at the end of the article

© 2015 Gomes et al. Open Access This article is distributed under the terms of the Creative Commons Attribution 4.0International License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, andreproduction in any medium, provided you give appropriate credit to the original author(s) and the source, provide a link tothe Creative Commons license, and indicate if changes were made. The Creative Commons Public Domain Dedication waiver(http://creativecommons.org/publicdomain/zero/1.0/) applies to the data made available in this article, unless otherwise stated.

Gomes et al. World Journal of Emergency Surgery (2015) 10:60 DOI 10.1186/s13017-015-0053-2

invasive management options including percutaneousdrainage, non-operative treatment and minimally invasivesurgery are available [6].Three imaging modalities are available in difficult

cases of acute appendicitis: Ultrasound (US), ComputedTomography (CT), and Magnetic Resonance Imaging(MRI). Trans-abdominal ultrasound should be the first-lineimaging test. Although there is a higher radiation burden,abdominal CT is superior to US and may be required inpatients with an equivocal US or if perforation is suspected.Low-dose unenhanced CT is equivalent to standard-doseCT with intravenous contrast agents in the detection of thefive signs of acute appendicitis (thickened appendiceal wallgreater than 2 mm, cross-sectional diameter greater than6 mm, increased pericolic fat density, abscess, and appendi-colith) [7]. However, as pointed out by Saar, despite allavailable technologies, it remains very difficult to achieve afalse negative appendectomy rates less than 10 % [8].

Operative versus non-operative treatmentBoth open appendectomy and laparoscopic appendectomyare acceptable techniques and can be used interchangeably.The laparoscopic treatment of uncomplicated grades ofacute appendicitis is well established and represent theapproach of first choice some time ago. However, well-conducted trials to help guide the treatment for all compli-cated grades of acute appendicitis are limited, especially bythe presence of bias and methodological flaws. However,the safety and efficacy of laparoscopy in the treatment ofthese cases is well established too [9–13].A recent meta-analysis by Varadhan et al. 2015 [14]

assessed four randomized controlled trials about safetyand efficacy of antibiotics compared with appendectomyfor treatment of uncomplicated acute appendicitis[15–18]. The primary outcome measure was the incidenceof complications and secondary outcome was the efficacyof treatment. 900 patients (470 antibiotic treatment, 430appendectomy) met the inclusion criteria. Antibiotic treat-ment was associated with a 63 % (277/438) success rate at1 year. Meta-analysis of complications showed a relativerisk reduction of 31 % for antibiotic treatment comparedwith appendectomy. The authors concluded that antibi-otics are both effective and safe as primary treatment forpatients with uncomplicated acute appendicitis. Initialantibiotic treatment deserves consideration as a primarytreatment option for early-uncomplicated appendicitis.Similarly, the study NOTA (Non Operative Treatment

for Acute Appendicitis), assessed the safety and efficacy ofantibiotic treatment for suspected acute uncomplicatedappendicitis and monitored the long-term follow-up ofnon-operated patients. One hundred fifty-nine patientswith suspected appendicitis were enrolled and underwentnon-operative management with amoxicillin / clavulanate.The follow-up period was 2 years. Short-term (7 days)

non-operative failure rate was 11.9 %. All patients withinitial failures were operated within 7 days. At 15 days, norecurrences were recorded. After 2 years, the overallrecurrence rate was 13.8 %. The authors concluded thatantibiotics for suspected acute appendicitis are safe andeffective and may avoid unnecessary appendectomy, redu-cing operation rate, surgical risks, and overall costs [19].Although interesting and reducing the false negative ap-

pendectomy rate, both studies also contain methodologicalflaws, like the patients recruitment, surgery approach(laparotomy/laparoscopy), different antibiotics prescriptionand images diagnostic method criteria (CT scan / Ultra-sound). In addition, the success rate of 63 % is very low andthe relative risk of complication reduction very high. There-fore, the laparoscopic treatment of non-complicated acuteappendicitis may show much less complication rates andrepresent the treatment of choice with acceptable falsenegative appendectomy rate about 10 % [11, 20].

Histologic diagnosisAs a rule, the acute appendicitis diagnosis was establishedaccording to the transmural appendix inflammation (neu-trophilic infiltration of the mucosa, submucosa, and muscu-laris propria). The histologic assessment also defined thedifference between endoappendicitis (neutrophils withinmucosa and mucosal ulceration) and periappendicitis(inflammation restricted to serosa and sub-serosa) [21].

Why to propose a new acute appendicitis gradingsystem?The laparoscopic grading system of acute appendicitisproposed by Gomes et al. [20] is limited by its exclusivefocus on just the intraoperative aspects (Table 1).Complicated grades (phlegmon, abscess and/or diffuseperitonitis), are now reliably distinguished from uncom-plicated cases by clinical and imaging findings. Becausethe treatment options for these complicated cases ofacute appendicitis includes non-operative modalities, anew comprehensive grading system for acute appendi-citis is necessary (Table 2).It was idealized a grading system for acute appendicitis

that incorporates clinical presentation, imaging and lap-aroscopic findings. The goal of this new grading systemis to provide a standardized classification to allow moreuniform patient stratification for appendicitis researchand to aid in determining optimal management accord-ing to grade (Table 2).

New acute appendicitis grading systemGradesGrade- 0 (normal looking)The grade 0 refers to the non-rare situation surgeon mayfaces, when the patient has a clinical diagnosis of acuteappendicitis and laparoscopy shows a macroscopically

Gomes et al. World Journal of Emergency Surgery (2015) 10:60 Page 2 of 6

“normal looking appendix”. In such case, if the appendixlooks normal on laparoscopy but another disease is foundto be the cause of the patient’s symptom, then the appendixshould be left in situ [22]. The 10-year follow-up by vanDalen et al. [23], demonstrated the safety of this approachin women. The situation is more complicated when the ap-pendix shows no signs of inflammation and no other dis-ease can be found (Fig. 1). Weighting the disadvantages of anegative appendectomy against the risk of overestimating acase of appendicitis is difficult. If symptoms and signs aretypical for appendicitis, most surgeons still consider advisedto perform an appendectomy, because in early appendicitis,the inflammation may be limited to intramural layers [11].In surgical cases of pelvic endometriosis, surgeons need

to preoperatively inform that appendix is found frequentlyinvolved, regardless the presence of concurrent symptomsor gross finding of the appendix. Furthermore, surgeonsshould take into account the possibility of performing anincidental appendectomy [24].

Grade-1 (inflamed)Gomes et al. in 2012, published a series of 186 patientswho underwent a laparoscopic appendectomy, according tothe Laparoscopic Grading System for Acute Appendicitis(Table 1). This grading system has been developed to strat-ify the disease according to the inflammatory findingsoccurring within the appendix and the abdominal cavity.The impact of the grade on surgical site infection was alsoexamined [20]. This score was externally validated in acohort of 112 consecutive cases of complicated acute ap-pendicitis patients by Di Saverio et al, where all patientshad Gomes scores II–V and the scores were correlated withthe outcomes [25]. Based on this series the safety and effi-cacy of laparoscopy compared to open appendectomy wasalso examined. The laparoscopic grading system was usefulin stratify the disease; contributing and highlights someaspects, whose laparotomy could not be able to show at thesame amplitude (Fig. 2) [20].In addition, Gomes et al. documented an unusual situ-

ation. About 10 % of the patients where appendix presentedwith hyperemia, edema and fibrin exudates had a significantplasma exudation into the abdominal cavity. The study ofthe exudates diagnosed the presence of gram-negative bac-teria in 10 % of the analyzed samples. These data could ex-plain, at least partially, that acute appendicitis may getcomplicated with development of postoperative peritonitisand intra-abdominal abscesses after simple appendectomies,especially when antimicrobial prophylaxis was not adminis-trated. Excessive plasma exudation in the absence of necrosisand/or perforation of resected appendices could be explainedby bacterial translocation and plasma transudation [20].

Grade- 2A and 2B (necrosis)Complicated appendicitis refers to gangrenous and/orperforated appendix, which may lead to abscess formation

Table 2 Proposal of a new grading system of acute appendicitisbased on clinical, imaging and laparoscopic findings (2015)

Non-Complicated Acute Appendicitis

Grade 0 - Normal Looking Appendix (Endoappendicitis/Periappendicitis).

Grade 1 - Inflamed Appendix (Hyperemia, edema ± fibrin without orlittle pericolic fluid).

Complicated Acute Appendicitis

Grade 2 – Necrosis A - Segmental Necrosis. (without or littlepericolic fluid).

B - Base Necrosis. (without or littlepericolic fluid).

Grade 3 - InflammatoryTumor-

A Flegmom.

B - Abscess less 5 cm without peritonealfree air.

C - Abscess above 5 cm withoutperitoneal free air.

Grade 4 - Perforated - Diffuse Peritonitis with or without peritonealfree air.

Note: Proposal for a new acute appendicitis grading system based on clinical,imaging and laparoscopic findings. (±) = Presence or absence offibrinous exudate Gomes et al. (2015).

Fig. 1 “Normal looking appendix” without any other intra-abdominaldisease and suggestive clinical set. The appendix was removed andthe histopathological study shows intraluminal inflammation (Grade 0)

Table 1 Laparoscopic grading system of acute appendicitis

Grade Laparoscopic findings

Grade 0 Normal looking appendix

Grade 1 Hyperemia and edema

Grade 2 Fibrinous exudate

Grade 3A Segmental necrosis

Grade 3B Base necrosis

Grade 4A Abscess

Grade 4B Regional Peritonitis

Grade 5 Difuse Peritonitis

Note: From Gomes et al. 2012 [13]

Gomes et al. World Journal of Emergency Surgery (2015) 10:60 Page 3 of 6

and degrees of peritonitis [26]. Therefore, these grades bydefinition are complicated cases of acute appendicitis.Nevertheless, the specific grade study, showed that in thegrade 2A, the necrosis was an isolated phenomenon,restricted to the appendix, without or with minimal localexudation (Fig. 3). The majority of patients had anuneventful recovery and were discharged in the next post-operative day. More importantly, they had a clinical coursesimilar to those with non-complicated appendicitis (grade0, 1). They received short course antimicrobial therapy (3to 5 days) and post-operative complication was a rareevent. By the way, recent observational cohort study fromvan Rossem et al. showed that after appendectomy forcomplicated appendicitis, 3 days of antibiotic treatment isequally effective as 5 days in reducing postoperative infec-tions [27].

About 3.2 % there was presence of necrosis involving theappendicular base, at the level of its insertion on cecal wall(grade 2B). This condition makes the operation even moredifficult and requires experience from the surgical teamwith intra-corporeal suturing, mainly when endostapler isnot routinely used, justifying a new specific grade, which israrely studied during laparoscopic appendectomy. Now-adays, this grade represents the most important situation,where the endostapler is used to closure the appendicealstump in the Service. In the other grades the appendicularstump could be closure of different ways (endostapler,endoloop, metallic and polymeric clip and others one). Weprefer its management by T-400 metallic endoclip, whichis less expensive and have demonstrated safety and effect-iveness in a prospective observational study [20]. Inaddition, it is oriented operating the patients under DayHospital way. The study of Alvarez and Voitk [28], shouldbe highlighted because, according the authors, in the am-bulatory management of acute appendicitis (Day Hospital),the patients discharge is occurring less than 24 h after

Fig. 2 The image shows hyperemia and edema of appendix, withoutfibrinous exudate (Grade-1)

Fig. 3 Acute appendicitis with segmental necrosis (black arrow). Observethat the appendiceal base was not compromised by inflammatory andnecrotic process, allowing appendicular stump closure by metallic clip(white arrow) In a healthy tissue (Grade 2A)

Fig. 4 The CT scan of abdomen showing an inflammatory tumor inthe lower right quadrant. The patient was managed with antibioticsonly; i. e non-operative treatment. (Grade 3A)

Fig. 5 Acute appendicitis complicated with inflammatory tumor and anabscess less than 5 cm, managed by laparoscopic approach (Grade 3B)

Gomes et al. World Journal of Emergency Surgery (2015) 10:60 Page 4 of 6

appendectomy and this recommendation was adopted forgrades 0,1, 2 [28].

Grade- 3A - 3B - 3C (perforated - inflammatory tumor)As it is already well known, sometimes the inflammation ofthe appendix may be enclosed by the patient’s own defensemechanisms, by the formation of an inflammatory phleg-mon or a circumscribed abscess of different diameter, oftenpresenting some days after the onset of symptoms [29]. Infact, an inflammatory tumor in the right lower quadrantrepresents a spectrum, at least of three physiopathologystages of the acute appendicitis, very similar to what hap-pens in the acute diverticulitis of sigmoid colon: phlegmon,inflammatory tumor with <5-cm abscesses and inflamma-tory tumor >5-cm abscess (Fig. 4). Thus, once again, suchpatients should not be considered as a whole, without dis-tinction, since they have different aspects with regard to,physiopathology, treatment, complications, disease recur-rence and prognosis. Moreover, according to Stefanidis etal 2008, acute abdominal pain lasting less than 7 days [30].Therefore, assuming that we are evaluating patients withacute and subacute disease, since mostly patients classifiedwithin these grades, had the onset of symptoms occurringinto seven or more days. These patients receive longcourse (5–10 days) antimicrobial therapy according theirclinical post-operative recovery (Fig. 5).

Grade- 4 (perforate - diffuse peritonitis)Controversy exists regarding the laparoscopic approachin the treatment of acute appendicitis complicated withdiffuse peritonitis. The chance of potential surgical com-plications is high and consequently the outcomes arepoorly documented. Our literature review found onlytwo articles investigating the issue [31, 32]. Although theresults seems to favor the use of laparoscopy, only alarge multi-institutional study with appropriate designwill be able to answer this question (Fig. 6).

SummaryIn summary, the new appendicitis grading system is basedon three aspects of the disease. The clinical, imaging andlaparoscopic findings and could be tested in multicenterobservational study within the World Society of Emer-gency Surgery, in order to assess its actual practicality. Itwill enable the creation of homogeneous groups of patientswith disease in the same well-defined stage. Ultimately, thegoal of this grading system is to aid in determining optimalmanagement according to grade, and to provide a stan-dardized classification system to allow more uniformpatient stratification for appendicitis research.

Competing interestsThe authors have no conflicts of interest ties or financial funding source’ todisclose.

Authors’ contributionsCAG, MS, SDS: conception design and coordination and helped to draft themanuscript, acquisition of data, analysis and interpretation of data, entiremanuscript reviewer. FC, FC, LA: Participated in the sequence alignmentand revising it critically for important intellectual content; KI, DD: Participated inthe sequence alignment, design and revising it critically for important intellectualcontent; FCG, CCG: have made substantial contributions in the graphic art andcontribution in the manuscript conception and revision. All authors read andapproved the final manuscript.

AcknowledgementsManuscript produced at Surgery and Internal Medicine Unit. Monte SinaiHospital, Juiz de Fora, Minas Gerais, Brazil.*Presented in part at last World Society of Emergency Surgery (WSES)Congress, 2015 in Jerusalem – Israel.

Author details1Surgery Department, Therezinha de Jesus University Hospital, Medical andHealth Science School, Surgery Unit, Federal University of Juiz de Fora (UFJF),Rua Senador Salgado Filho 510 / 1002, Bairro Bom Pastor, Juiz de Fora, MinasGerais 36021-660, Brasil. 2Department of Surgery, Macerata Hospital,Macerata, Italy. 3Trauma Surgery Unit, Maggiore Hospital, Bologna, Italy.4General Surgery I, Papa Giovanni XXIII Hospital, Bergamo, Italy. 5EmergencySurgery Department, Maggiore Parma Hospital, Parma, Italy. 6University ofCalifornia, San Francisco, USA. 7Department of Surgery (K.I.), Keck School ofMedicine of University of Southern California, Los Angeles, CA, USA. 8InternalMedicine Departament, Therezinha de Jesus University Hospital, Medical andHealth Science School, Juiz de Fora, Brazil. 9Internal Medicine Departament,Monte Sinai Hospital, Juiz de Fora, Minas Gerais, Brazil.

Received: 27 August 2015 Accepted: 24 November 2015

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